This work has as its main objective providing the reader all the necessary tools to successfully design a frame to be used as a reaction structure for a servo-hydraulic testing machine. This kind of equipment is very common in the industry in order to acquire the mechanical properties of specific materials. This work uses a pre-defined combination of hydraulic piston and servo-valve, both fatigue rated. The development of an analytic model is necessary in order to account all the deformations and internal loadings of the machine, further being verified by a finite elements analysis. To fulfill its purpose, the machine needs to correctly accommodate all the peripheral equipment and resist the static and dynamic loadings that it will be subject to, staying under pre-defined values of deflection and vibration.